The present invention relates to trimming apparatus which cut vegitation such as grass and weeds and more particularly, to a filament-type trimming apparatus of the type which automatically feeds out additional filaments by reason of centrifugal force generated responsive to the speed of rotation of a casing.
Trimming apparatus of this kind generally require means for feeding out additional filaments when the projecting end portions of filaments are worn or broken off during its use. One of such means heretofore available is such that additional filaments are fed out by hitting the bottom of a trimming head on the ground so as to disengage a spool within a casing from a cover or bottom plate and independently rotating the same to unwind the desired amount of the filaments. However, such means is incapable of regulating the speed of rotation of the spool and the feeding amount of additional filaments. Accordingly, the filaments are, from time to time, likely to be fed more than they are necessary, thereby increasing the cutting radius of the cutting filaments while they are cutting vegetation and causing the operator to be in a dangerous operating situation.